<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>upload</title>
</head>
<body>
    <div>
        <input type="file" name="file" onchange="uploadFile(this);">
    </div>
    <div>
        <pre id="ret-content"></pre>
    </div>

<script>
    function uploadFile(t){
        if(t.files.length <= 0) return;

        let fm = new FormData();

        fm.append('image', t.files[0])

        fetch('/upload', {
            method: 'POST',
            body: fm
        })
        .then(res => {
            return res.text();
        })
        .then(text => {
            let d = document.getElementById('ret-content');
            d.innerHTML = `<img src = "/image/${text}"` + `style = "width:80%;height:auto;"`;
        });
    }
</script>

</body>
</html>